godan verb (-su), transitive verb
knead again; re-knead; knead thoroughly
Literally to knead something again or repeatedly, often with the nuance of working it over until it becomes messy or complicated. Figuratively used for rehashing or complicating an issue.
パン生地を何度もこね返した。
I kneaded the bread dough over and over again.
彼は会議で同じ話をこね返し
He keeps rehashing the same story in meetings.